The one-leg stand test is a standardized field sobriety test (SFST) that police administer during traffic stops to determine whether you are under the influence of alcohol or drugs.
For the one-leg stand test, the officer instructs you to stand with one foot about six inches off the ground and count aloud by thousands (one-thousand-one, one thousand-two, etc.) for 30 seconds. If you
- sway,
- use your arms to balance,
- hop, and/or
- put your foot down,
the police can use that as evidence you may have an illegal blood alcohol concentration.
In this article, our California DUI attorneys discuss:
- 1. One-leg stand instructions
- 2. The four “clues”
- 3. Reliability
- 4. Other field sobriety tests
- Additional resources
1. One-leg stand instructions
Below are the one-leg stand test instructions given by the National Highway Traffic Safety Administration (NHTSA) to DUI law enforcement officers on how to administer the one-leg stand sobriety test:
STEP 1
Provide the DUI suspect the instructions listed below and from a position of interrogation (that is, with your weapon away from the suspect):
STEP 2
Say: STAND WITH YOUR HEELS TOGETHER AND YOUR ARMS DOWN AT YOUR SIDES LIKE THIS
- Demonstrate how you want the suspect to stand.
STEP 3
Say: WHEN I TELL YOU, RAISE ONE LEG ABOUT SIX INCHES OFF THE GROUND AND HOLD THAT POSITION. AT THE SAME TIME COUNT RAPIDLY FROM 1001 TO 1030, WHILE WATCHING YOUR FOOT
- Demonstrate this to the suspect (though do not look at your foot when conducting the demonstration).
STEP 4
Say: DO YOU UNDERSTAND?
- Do not continue until the suspect indicates that they understand.
STEP 5
Say: BEGIN BY RAISING EITHER YOUR RIGHT OR YOUR LEFT FOOT.
- At the end of the count or after about 30 seconds, if the count is slow, tell the suspect to put their foot down if necessary.1
2. The four “clues”
In order to gauge whether you are intoxicated, law enforcement officials will typically watch for four “clues” of intoxication during the administration of the one-leg stand test:
- You sway while balancing: This refers to side-to-side or back-and-forth motion while you maintain the one-leg stand position.
- You use your arms for balance: You move your arms six or more inches from the side of your body in order to maintain balance.
- You hop: You are able to keep one foot off the ground, but you resort to hopping in order to maintain balance.
- You put your foot down: You are not able to maintain the one-leg stand position, putting your foot down one or more times during the 30-second count.
The officer will fail you if either:
- you exhibit at least two different clues and/or
- you put your foot down three or more times during the 30-second period.2
3. Reliability
According to government-sponsored studies, the one-leg stand test is only 65% accurate in determining whether a driver has an unlawful blood alcohol concentration.3 In short, more than one out of three people who fail the test are not intoxicated.
The one-leg stand becomes even more unreliable when any of the following is true:
- the floor surface is uneven, slippery, soft, or wet
- the lighting is inadequate
- you are elderly (over 60), overweight by 50 or more pounds, or have problems with your back, legs, feet, or inner ear
- you are mentally disabled or have brain damage
- You are wearing unsuitable footwear or clothing inhibiting your movements
- the officer does not time the test correctly
- the officer moves during the test, distracting you
4. Other field sobriety tests
The one-leg stand test is one of three standardized field sobriety tests (SFSTs). The other two are:
- the horizontal gaze nystagmus test (the eye test) and
- the walk and turn test.
These three tests are considered “standardized” mainly because they have been the focus of various scientific studies noticeably establishing the connection between the three tests and DUI impairment.
Out of all the standardized field sobriety tests administered by law enforcement officials, the one-leg stand test has proven to be the least scientifically reliable.4
5. Additional resources
For more information, refer to the following:
- Alcoholics Anonymous – 12-step program for overcoming alcoholism.
- Drunk Driving Overview – NHTSA page on drunk driving statistics and prevention.
- Impaired Driving: Get the Facts – CDC fact sheet on impaired driving.
- Driving Under the Influence (DUI) – California DMV page on driver license suspension for DUIs.
- MADD – Non-profit organization devoted to stopping drunk driving.
Legal References
- SFST DWI Detection and Standardized Field Sobriety Testing, Instructor Guide, NHTSA.
- Same.
- Same.
- Same. See also Michael P. Hlastala et. al., Statistical evaluation of standardized field sobriety tests, Journal of Forensic Science (2005).